The number of women Veterans is increasing due to changes in the composition of the active duty military, and understanding the healthcare needs of this growing segment of the patients we serve is critical. Insomnia complaints are more common among women than men, with a mean prevalence of over 23% among US women. Insomnia (defined as sleep disturbance that is sufficiently severe to cause distress or impact functioning), is a significant public health concern that contributes to lost productivity, psychological distress, medical morbidity, and mortality risk. In a recent paper on transformation of care for women Veterans, Yano et al. included sleep issues as part of the VA Women's Health Research Agenda for the Future; however, systematic reviews of VA women's health research (2006 and 2011) did not identify any prior studies of sleep disorders among women Veterans. In 2011 we completed the first descriptive study of sleep problems among women Veterans who receive VA Healthcare (HSRD PPO 09-282-1; PI: Martin). We found high rates of insomnia (54% of respondents) and comorbid conditions that may impact treatment acceptability and delivery. We also found that women Veterans with insomnia preferred non-medication treatments over medications, and that they were most likely to access this treatment if it were delivered in individual format (rather than groups). There is a growing literature on treatment of insomnia among individuals with comorbid conditions, suggesting that insomnia treatment may lead to meaningful and durable improvements in sleep quality and other symptoms. The proposed study is a randomized trial to compare a novel treatment, Acceptance of the Behavioral Changes to treat Insomnia (ABC-I), which combines behavioral components of Cognitive-Behavioral Therapy for Insomnia (CBT-I), with components of Acceptance and Commitment Therapy (ACT) to improve adherence to the behavioral recommendations of CBT-I. The objectives are: 1) to compare dropout rates and adherence to behavioral recommendations between the ABC-I program and a similarly-structured CBT-I program, 2) to compare the effectiveness of the ABC-I in improving sleep/wake patterns from baseline to post-treatment to a similarly-structured CBT-I program, and 3) to compare the maintenance of improvements in sleep/wake patterns across the two treatment programs 3-months after the end of treatment. Women with insomnia will be identified using methods developed in our previous pilot study. A brief survey will be mailed to approximately 5,000 women Veterans who have received healthcare within 6 months from the VA Greater Los Angeles Healthcare System. All women who return the survey indicating symptoms of insomnia will be contacted by phone and invited to participate in the treatment study. Exclusion criteria will be limited to severe or unstable medical/psychiatric disorders, the presence of moderate-to-severe sleep apnea, or barriers to attending the treatment sessions (e.g., live too far away, no access to transportation). ABC-I will be provided in 5 one-on-one sessions to women Veterans with insomnia by a trained interventionist (n=74) and will be compared to a similarly-structured CBT-I program (n=74). Adherence and attrition will be measured in both conditions. Sleep quality (self-reported and objectively measured), psychiatric symptom severity and quality of life will be assessed at baseline, post-treatment and at 3-month follow-up. ANOVA will be used to test for differences between groups in adherence and attrition. Equivalency/noninferiority methods will be used to determine whether sleep-related outcomes for ABC-I are comparable to CBT-I, using both intent to treat and per protocol analyses. With the proposed sample size, we will have sufficient power to test the study hypotheses.